Aircraft galley carts are used to store food items such as airline meals for distribution to passengers by flight attendants. Airline meals are typically prepared offsite by a caterer who then delivers the meals to the aircraft just prior to departure. Airline operators are required to maintain food items at a safe temperature prior to distribution to passengers. For certain long-haul flights, the food items must be continuously maintained at relatively low temperatures (e.g., below 4 degrees Celsius) for extended periods of time such as up to 15 hours or longer as required by certain agencies.
Airline operators typically use one of several methods for maintaining the food items within the galley carts below a required minimum temperature. For example, the galley carts may be cooled by one or more galley chillers located in the galley area of the aircraft cabin. Each galley chiller produces cooled air which may be passed over and around the exterior of the galley cart to maintain the interior below a predetermined temperature. Alternatively, each one of the galley carts may be directly connected to an external duct or plenum in the galley area such that cooled air from the chiller unit is passed from the duct or plenum directly through the interior of the galley cart.
Although generally effective for their intended purposes, galley chillers possess certain drawbacks which detract from their overall utility. For example, each one of the galley chillers includes an active mechanical refrigeration unit for producing cooled air to be passed over or passed through each galley cart. The mechanical refrigeration units add to the overall weight of the aircraft reducing payload capacity and increasing fuel consumption. In addition, mechanical refrigeration units typically produce noise that adds to aircraft cabin noise and reduces passenger comfort. A further drawback associated with conventional galley chillers is that the refrigeration units and associated ducting occupy valuable space in the galleys which reduces the total amount of cabin area available for passenger seating
Additional drawbacks associated with conventional galley chillers include relatively high manufacturing and installation costs due to the complexity of the mechanical refrigeration units. Furthermore, the mechanical refrigeration units typically require routine maintenance at regular service intervals which adds to the operating costs of the aircraft. In addition, the mechanical refrigeration units may consume significant amounts of electrical power which must be provided by the aircraft power system. For example, a single conventional galley chiller installed in an aircraft may draw approximately 4 kilowatts of power from the aircraft power system. To accommodate the power requirements, the galley chiller may require heavy gauge electrical feeder lines and associated circuit breakers, all of which adds to the weight and space requirements of the aircraft.
As can be seen, there exists a need in the art for a system and method for maintaining food items on an aircraft below a desired temperature for extended periods of time and which eliminates the need for galley chillers and their associated mechanical refrigeration units, electrical feeder lines and other hardware. In this regard, there exists a need in the art for a galley cart capable of maintaining the cart interior at a relatively low temperature for extended durations and which is low in cost, simple in construction and which occupies a minimal amount of cabin space.